The liver is an important tissue to investigate for obvious reasons. Although in vivo studies of the liver regarding structure and functions have been rewarding, observation of cellular and subcellular levels under tissue culture system would offer new insight into its function and interaction with its environmental conditions including carcinogens. We have been attempting to develop a method for maintaining adult liver cells in culture with highly successful results. This technique would be applicable to both mammalian and human livers. The goal of our project is to analyze the early events of carcinogenic transformation of normal liver cells during and immediately after chemical carcinogen treatment. The chemical carcinogens we have been using are aflatoxin Bl, dimethyl-nitrosoamine and thioacetamide.